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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Mt. Kilimanjaro and the global retreat of glaciers

What the science says...

Mount Kilimanjaro's shrinking glacier is complicated and not due to just global warming. However, this does not mean the Earth is not warming. There is ample evidence that Earth's average temperature has increased in the past 100 years and the decline of mid- and high-latitude glaciers is a major piece of evidence.

Climate Myth...

Mt. Kilimanjaro's ice loss is due to land use
'Gore claims the snowcap atop Africa's Mt. Kilimanjaro is shrinking and that global warming is to blame. Yet according to the November 2003 issue of Nature magazine, "Although it's tempting to blame the ice loss on global warming, researchers think deforestation of the mountain's foothills is the more likely culprit. Without the forests' humidity, previously moisture-laden winds blew dry. No longer replenished with water, the ice is evaporating in the strong equatorial sunshine."' (James Taylor)

Indeed deforestation seems to be causing Mount Kilimanjaro's shrinking glacier so Gore got this wrong. But Philip Mote, author of the study in Nature, puts it in perspective: "The fact that the loss of ice on Mount Kilimanjaro cannot be used as proof of global warming does not mean that the Earth is not warming. There is ample and conclusive evidence that Earth's average temperature has increased in the past 100 years, and the decline of mid- and high-latitude glaciers is a major piece of evidence."

Comments

To say that climate change is definitely not even partially responsible for the loss of glacier ice mass on Kilimanjaro is an inaccurate misrepresentation of the science. As Raymond Pierrehumbert's article that you linked to made clear, it is likely to be at least partially responsible.

Furthermore, Gore did not "get it wrong" as you claim - in the movie, the retreat of Kilimanjaro is not claimed to be purely due to global warming , but it is given as an example of the sort of thing one can expect in a warmer world, and it is quite true that loss of major glaciers is something we can expect.

I also think you ought to link to the global glacier mass balance graph at on the National Snow and Ice Data Center (NDIS) graph here, from which one can see that the worldwide trend is sharply downwards; and there is no dispute in the peer reviewed literature that this is mostly due to climate change. Admittedly, Gore could and should have chosen a better example than Kilimanjaro, such as the Andean glaciers, but he didn't "get it wrong", he just illustrated a valid and accurate point with a poorly-chosen illustration.

Finally, I think you should point out that hundreds of millions of people (and huge ecosystems) rely for their water on the annual glacier summer melts that in many cases may cease during the next 50-100 years, as mountain glaciers start to disappear. This includes a large proportion of China's population, all of the “Stans” (Pakistan, Uzbekistan, Turkmenistan, etc.) and most of the Andean countries in South America (e.g. see here , here and here).

Response: Dave, all good points and I confess updating the Mt Kiliminjaro page is high up on my to-do list. Thanks for the link suggestions (I do link to the NSIDC graph elsewhere but here is a good place also) - will attend to this shortly as soon as time permits.

Lonnie Thompson, an expert in ancient climates at Ohio State University ... said ... "Kilimanjaro's glaciers are melting so quickly ... that the mountain lost nearly a quarter of its ice from 2000 to 2006 ... [it points out that melting is accelarating everywhere and adds] ... If you look at what's happened to these glaciers, they're not just retreating, they're accelerating [their retreat]," he said. "And it raises the question of whether this might be a fingerprint of [human-caused global] warming.

In other words, even if the melting of Kilimanjaro prior to 2000 contains 0% influence from climate change (which is unlikely), the influence of climate change on the melt rate of Kilimanjaro since 2000 is almost certainly well above 0%. No other factor, including deforestation, can credibly account for the sudden acceleration post-2000.

"Melting glaciers in the Himalayas could lead to water shortages for hundreds of millions of people"

Admittedly this article has the disadvantage that it quotes a WWF study - it would be nice to find a similar one that was independent of any lobby group. But it's mainstream stuff and worth quoting if you can't find a better one on the Himalayas' glacier melt and the likely effect of this on neighbouring countries.

I think it's worth pointing out that Kilimanjaro has never held much water in it's glaciers and that summer melting has never been a source of water for the people below unlike in other areas.

Interestingly enough, there seems to be some suggestions, within the scientific community, that increased precipitation, caused by global warning, may actually increase the amount of ice on Kilimanjaro and save the glacier.

Trent, based on the Mölg paper you reference, a more appropriate interpretation would be that modelling suggests that "the hypothesis that local LCC is another forcing of glacier loss on Kilimanjaro cannot be corroborated".

And thus refuting two (here and here) of Dr. Roger Pielke, Sr's papers on LCC (land-cover-change), as they might apply to Mount Kilimanjaro.

Trent @5 good find. As someone who has undertaken some work in this field, I never found the argument/hypothesis land use change on the lower slopes argument affecting the precipitation on the summit (almost 6000m) very compelling.

However, the fake skeptics (e.g., WUWT and Marc Morano ) have been happily perpetuating this idea for some time now.

Contrary to the what the fake skeptics claim, Mölg et al. conlcude:

"Thus, for the moment, the hypothesis that local LCC is another forcing of glacier loss on Kilimanjaro cannot be corroborated."

And

"We therefore argue that attribution of glacier change and variability to large-scale climate dynamics is unlikely to be distorted by local LCC."

I'm not sure what Pielke Senior has to say about this particular issue. Oddly enough, despite his very vocal critique of models, he was happy to endorse a modelling study on his blog by Fairman et al. (2011) which suggested that vegetation was affecting the precipitation at medium and low levels (not the summit) of Kilimanjaro.

Interestingly Mölg was a co-author on the Fairman et al. (2011) paper. I have not yet seen Mölg et al. (2012) featured on Pielke's blog....

I am still at a loss on why the glaciers of Kilimanjaro are melting. I understand that temperatures at the summit have only risen a trivial amount. I know the loss has been blamed on increased sublimation but that leads to another question of why sublimation has increased in East Africa?

I know that past researchers have minimized the role that AGW has played, yet I am still suspicious of why a glacier that has been around for at least 11,700 years would just start to melt at the same time as other mountain glaciers of the world.

Trent1492 @8, I have always been suspicious of fake skeptic claims that Kilimanjaro's snows did not melt as a consequence of global warming. As temperature increases, ice sublimates faster. The area around Mount Kilimanjaro shows a 0.5 to 1 degree anomaly relative to the 1951-80 mean for December through to February (GISTEMP), the hottest time of year for Mount Kilimanjaro. (It shows the same anomaly on annual data as well. Clearly, there has been an increase in sublimation due to temperature on Kilimanjaro. Consequently the common fake skeptic claim that the summit of Mount Kilimanjaro is still below freezing, and that therefore global warming is not responsible for the loss of ice is a non-sequitur.

Against this, insolation rates and humidity also effect rates of sublimation. Aerosol Optical Depth has increased with time over the twentieth century, although at a much reduced rate between 1975 and 2000, which would tend to reduce sublimation rates. However, this 2004 study, by the same lead author as the paper to which you link, strongly suggests that change is cloud cover is the dominant factor, with reduced cloud cover resulting in greater insolation and hence greater sublimation. Until a study shows the regional change in cloud cover is a consequence of global warming, it is not possible to conclude categorically that global warming is the cause of the ice loss.

The paper you linked @5 (actually, the news report for me, as the paper is behind a paywall) is very interesting. From the news report and abstract, it does not rule out Land Cover and Land Use Changes as a cause of the reduced as the cause of the ice melt. It does mean, however, that claims that global warming was not the cause of the ice loss on Kilimanjaro are unproved at best. It shows that LC?LUC are probably not the cause of changes in cloud cover at the peak of Kilimanjaro, but does not show that global warming is.

Of course, given that the claim that Kilimanjaro did not lose its snow due to global warming is at best unproved, that certainly means Kilimanjaro is not the counter example to global glacial shrinkage due to global warming that fake skeptics pretend it is.

The mount Kilimanjaro glaciers are inherently unstable: the ice at the bottom of the glacier touching the rocks melts, the glaciers lose their ‘grip’ on the mountain and ‘overhangs’ occur where the ice at the base has melted away, leaving just the ice at the top to survive.